Uncertainty and Reliability Analysis of Jacket Platform

Abstract

Reliability analysis of a jacket platform presently operating in the North Sea is performed. The limit states correspond to design criteria for each structural component. For the tubular columns, beam buckling, shell buckling and maximum allowable stress are considered. For the tubular joints the punching shear failure mode is analyzed. A slightly redesigned version of the jacket is also considered for assessment of the inherent reliability level of the relevant design code. Latin hypercube sampling is employed for simulating vectors of realizations of basic variables. Probability distributions of extreme dynamic load effects are subsequently identified based on a sequence of response analyses. Reliability analysis is performed for selected structural components by FORM/SORM techniques. For a representative set of structural elements, the random variables influencing the load effects are ranked by means of results from an uncertainty analysis. Similarly, importance measures obtained as by‐products of the reliability analysis identify key variables of the failure functions. Finally, sensitivity of reliability measures to perturbations of basic distribution parameters are investigated by repeated analyses with revised input data.